Holotype instrument of a handhold-current-indicating form of zapper that also has dual duty cycle optionEdit
(Note: a "holotype" is an archived curated single physical specimen of a general type of something, by which all other specimens can be compared as to similarity.)
Usage of the basic original zapper as shown in Clark's books has found some facets which could be improved a bit:
- The output voltage waveform shows much loading of the signal with a solid handhold contact, leaving perhaps only three volts across the handholds. This was dealt with by adding an emitter-follower stage to the output.
- Since the signal cannot be felt during use, if there is a break in the handhold circuit anywhere restricting or preventing flow of zapper current through the person, one does not know if this is happening. Solution was to create an innovative circuit which discharges the body capacitance charge at the end of each zapper pulse, through a LED, whose brightness is then a measure of the performance of the entire handhold circuit.
- On rare occasions a somewhat more powerful, yet harmonic frequency filled zapper waveform might be useful. This was provided by adding a switch-selected option of the usual 35% pulse width, or a 65% pulse width.
This zapper design is made easy and cheap to build, starting with a "LED Flasher kit" from All Electronics (http://www.allelectronics.com/) (cost about $3 for the kit although mostly just using the kit's printed circuit board and a few of its electronic parts.) I used a small plastic food storage container as its chassis. Oddly, most of my records have vanished re this instrument's development, done many years ago; so here is what is easily available right now for this page, and ought to be enough for someone with some familiarity with building electronic gizmos to reproduce it. At this point one would need to create their own parts list from the schematic and layout shown above, to build this instrument.
It features a handhold current indicating LED; a buffered output for solid output waveform despite varying circuit load; using a low battery usage CMOS IC circuit; and a dual duty cycle mode to select the usual 35% duty cycle and also its complementary waveform, 65% duty cycle. Frequency is set for the usual zapper 30 KHz range pulse repetition rate, 9 Volt peak output.
One of this design's best features is the use of the CMOS 555 IC's FET that shorts to ground during the low-going part of the output signal; but in this design, this FET (pin 7 of the IC) is used to provide a fast dump of the charge absorbed by the body each positive part of the output cycle, dumping the charge through a LED so the amplitude of this current is quite visible to the experimenter; this shows that the entire circuit is working in use, as well as a qualitative measure of the zapping current through the user, including the adequacy of the dampness of the layer of wet paper towel covering the copper tubing handholds.Here it is upside down, but powered up and output also loaded by handholds, the green LED showing handhold current, its green LED's output light intensity is a function of the actual handhold current, thus providing feedback to the experimenter as to continuity of output circuit and load. The red LED is a power-on indicator.
Oscilloscope showing the standard zapper 35% duty cycle output waveform. The 65% duty cycle waveform option is the inverse of this one; that is, the part that is low voltage here is the part that is the high voltage part of the waveform.
The instrument has documentation kept inside it. Below is a copy of that documentation.
A more detailed description is available at http://www.scribd.com/doc/14394660/Building-an-Emergency-HRCType-Zapper